Submission #1269155

#	Time	Username	Problem	Language	Result	Execution time	Memory
1269155		gdragon	Knapsack (NOI18_knapsack)	C++20	100 / 100	58 ms	34376 KiB

knapsack

#include <bits/stdc++.h>
using namespace std;
#define TASK "long"
#define fi first
#define se second
#define ll long long
#define pb push_back
#define ALL(x) (x).begin(), (x).end()
#define GETBIT(mask, i) ((mask) >> (i) & 1)
#define MASK(i) ((1LL) << (i))
#define SZ(x) ((int)(x).size())
#define mp make_pair
#define CNTBIT(mask) __builtin_popcount(mask)
template<class X, class Y> bool maximize(X &x, Y y){ if (x < y) {x = y; return true;} return false;};
template<class X, class Y> bool minimize(X &x, Y y){ if (x > y) {x = y; return true;} return false;};
typedef pair<int, int> ii;
const int N = 1e5 + 5;
const int inf = 1e9 + 7;
const long long INF = (long long)1e18 + 7;
const int mod = 1e9 + 7;
void add(int &x, int y) {x += y; if (x >= mod) x -= mod;}
void sub(int &x, int y) {x -= y; if (x < 0) x += mod;}
int mul(int x, int y) {return 1LL * x * y % mod;}
// -----------------------------------------//
int n, S;
int weight[N], value[N], cop[N];
void read() {
    cin >> S >> n;
    for(int i = 1; i <= n; i++) cin >> value[i] >> weight[i] >> cop[i];
}
void sub1() {
    int cnt = S / weight[1];
    cout << 1LL * min(cnt, cop[1]) * value[1];
}
void sub2() {
    vector<long long> dp(S + 2, 0);
    for(int i = 1; i <= n; i++) {
        for(int j = 1; j <= min(cop[i], S / weight[i]); j++) {
            for(int k = S; k >= weight[i]; k--) {
                maximize(dp[k], dp[k - weight[i]] + value[i]);
            }
        }
    }
    cout << dp[S];
}
void lastSol() {
    vector<vector<long long>> dp(S + 5, vector<long long>(S + 5, 0));
    vector<pair<int, int>> f[2005];
    for(int i = 1; i <= n; i++) f[weight[i]].push_back({value[i], cop[i]});
    for(int i = 1; i <= S; i++) sort(ALL(f[i]));
    for(int i = 1; i <= S; i++) {
        for(int j = 1; j <= S; j++) {
            dp[i][j] = dp[i - 1][j];
            int p = f[i].size() - 1;
            int cnt = 0;
            if (f[i].size()) cnt = f[i].back().se;
            long long sum = 0;
            for(int k = 1; k <= j / i; k++) {
                if (cnt == 0) {
                    --p;
                    if (p < 0) break;
                    cnt = f[i][p].se;
                }
                if (p < 0) break;
                sum += f[i][p].fi;
                maximize(dp[i][j], dp[i - 1][j - k * i] + sum);
                --cnt;
            }
        }
    }
    long long ans = 0;
    for(int i = 0; i <= S; i++) ans = max(ans, dp[S][i]);
    cout << ans;
}
void solve() {
    lastSol();
    // if (n == 1) sub1();
    // else if (n <= 100) sub2();
    // else lastSol();
}
signed main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    if (fopen(TASK".inp", "r")) {
        freopen(TASK".inp", "r", stdin);
        freopen(TASK".out", "w", stdout);
    }
    int test = 1;
    //cin >> test;
    while(test--) {
        read();
        solve();
    }
    return 0;
}

Compilation message (stderr)

knapsack.cpp: In function 'int main()':
knapsack.cpp:84:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   84 |         freopen(TASK".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
knapsack.cpp:85:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   85 |         freopen(TASK".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 12 / 12
• Subtask 2: 17 / 17
• Subtask 3: 20 / 20
• Subtask 4: 24 / 24
• Subtask 5: 27 / 27